Alkynyloxy)alkyl and (alkenyloxy)alkyl carbamates

ABSTRACT

This invention is novel (alkynyloxy)alkyl and (alkenyloxy)alkyl carbamates, which are highly effective herbicidal agents.

United States Patent Cross et al.

[ Feb. 18, 1975 ALKYNYLOXY )ALKYL AND (ALKENYLOXY)ALKYL CARBAMATESInventors: Harrington Cross, Rocky Hill;

Charles Paul Grasso, Cranbury, both of N].

American Cyanamid Company, Stamford, Conn.

Filed: Mar. 26, 1973 Appl. N0.: 344,667

Assignee:

US. Cl 260/479 C, 71/100, 71/106,

260/453 A, 260/454, 260/455 A, 260/614 R,

Int. Cl ..C07c 127/14, C07c 127/16,

CQ7C 127/18 Primary Examiner-James A. Patten Attorney, Agent, or Firm-H.G. Jackson [571 ABSTRACT This invention is novel (alkynyloxy)alkyl and(alkenyl0xy)alkyl carbamates, which are highly effective herbicidalagents.

9 Claims, N0 Drawings ALKYNYLOXYlALKYL AND (ALKENYLOXY)ALKYL CARBAMATESBACKGROUND OF THE INVENTION 1. Field of the Invention The inventionpertains to novel organic chemicals useful as herbicides.

2. Description of the Prior Art.

m-Ureidophenyl carbamates are described as herbicidal agents in U.S.Pat. No. 3,434,822 (1969). Similarly, alkoxyalkylcarbamoyloxyphenylureas are described as herbicidal agents in Belgium Pat. No.742,291, issured .Ian. 30, I970. The compounds described in thesepatents are shown to be quite effective as preemergence andpostemergence herbicidal agents against certain species of undesirableplants when applied at rates between 1.5 pounds and 6 pounds per acre.However, it can also be seen that the activity of the describedcompounds are generally non-selective and are not recommended for use inthe presence of economically important crops, such as corn, cotton,soybeans or sorghum.

It would, therefore, be advantageous if more effective compounds couldbe found which would provide better control of undesirable plants ateven lower rates of application. Surprisingly, we have found that thecompounds of our invention are highly effective herbicidal agents whenapplied at rates as low as 0.06 pound per acre. We have also discoveredthat the compounds can be used for selective control of undesirableplants in the presence of several agronomic crops, such as corn, cotton.soybeans or sorghum.

SUMMARY This invention is novel (alkynyloxy)alkyl and (alkenyloxy)alkylcarbamates represented by the structure:

wherein R is hydrogen, hydroxyl or alkyl C -C R is hydrogen, alkyl, C Cor alkoxy C -C R is hydrogen,

R is hydrogen or n-alkyl C -C R and R are hydrogen or alkyl C -C R andR5 are hydrogen, alkyl C -C or halogen, preferably chlorine, bromine oriodine; X is sulfur or oxygen; and A is hydrogen, halogen (preferablychlorine or bromine) or alkyl' C -C provided that A and -O-CX-NHR aremetaand para-, respectively,

2 or or paraand meta-, respectively; and further provided that R, ishydrogen when R;, iseither and a process for the compound'manufacture.

Preferred compounds are those havingtheabove formula, wherein R ishydrogensR is methylor methoxy;

R is methyl; A is hydrogen; X is oxygen; R

- NHCXO- is metato the ureido group; R R R DETAILED DESCRIPTION Inaccordance with the invention, (alkynyloxy)-alkyl carbamates and(alkyenyloxy)alkyl carbamates, illustrated by the formula given above.are prepared by the interaction of an (alkynyloxy)alkyl isocyanate,(alkynyloxy)alkyl isothiocyanate, (alkenyloxy)alkyl isocyanate or(alkenyloxy)alkyl isothiocyanate on an appropriately substitutedhydroxyphenyl urea (II) in the presence of a base in an organic solventas shown below:

a, -HN-EO 4 wherein R R R R X and A represent the members describedabove.

In order to obtain the carbamates of the invention, the reactionconditions must be chosen carefully. The phenol (II) can be eithersuspended or dissolved in an organic solvent, though complete solutionresults-m higher yields. Tetrahydrofuran is an excellent solvent for thereaction, but many of the phenols react equally well in other solvents,such as diethyl ether, p-dioxane, dimethylformamide, acetone, ethylacetate, methyl isobutyl ketone, benzene and the like. Addition of abase or catalyst to the reaction mixture is also beneficial. This isdemonstrated by the fact that improved product yields are obtained withthe addition, to the reaction mixture, of a catalyst, such as dibutyltindiacetate or a molar equivalent or excess of base, Triethylamine,pryridine, triisopropylamine and quinoline are typical of the baseswhich may be employed.

The isocyanates or isothiocyanates (III) are generated, preferably inethereal solution (e.g. diethyl ether or tetrahydrofuran), but are notisolated, at about C to C. by the action of silver cyanate or silverthiocyanate upon the appropriate chloromethyl ether. The reaction may begraphically illustrated as follows:

3 AgQNX R -C C-C l-O-CHCl -----a AgCML where R R R R R and X are asdescribed above.

Other procedures may also be employed to generate the isocyanates orisothiocyanates (Ill), e.g., other metal cyanates using a variety ofsolvent conditions (e.g., sodium cyanate-acetonitrile-benzene) may beused. 1

The cooled generated isocyanate or isothiocyanate solution is then addedslowly to a stirred solution of the phenol (ll), base and solvent. Afterthe addition and stirring, the solution is evaporated, washed with 1%icecold aqueous alkali solution, preferably sodium hydroxide, waterwashed and treated with an organic solvent, either to give a finalwash,or to crystallize the product.

Examples of the ureido phenols (ll) used in the preparation of the(alkynyloxy)alkyl and (alkenyloxy)alkyl carbamates (l) of the presentinvention are set forth below in Table I.

am I

2 reidogherio la Numbers 2, 5 through 9 and 16 were prepared by thereaction of the appropriate isocyanate with the appropriatelysubstituted-aminophenol in an aprotic solvent in the absence of base oracid catalysis.

Examples of the isocyanates and isothiocyanates (Ill) generated include,but are not limited to, those set forth in Table ll below. v

TABLE ll isocyanates and lsothiocyanates The compounds of the inventionare highly effective herbicidal agents. They provide selective controlof a wide variety of broadleaf weeds and grasses at very low rates ofapplication and can be used forpreemergence or postemergence control ofundesirable plants. They can be used alone or in combination with otherherbicides and are particularly effective when utilized for the controlof the undesirable weeds and grasses in the presence of agronomic crops,such as corn, cotton, soybeans and sorghum.

The active co'mpounds can be prepared as liquid or solid formulationsand appliedas such to the foliage of undesirable plants or to soilcontaining seeds of undesirable plants. I

Among the solid formulations which can be prepared are dusts, dustconcentrates, wettable powders and 75% by weight of the active compoundis applied to or mixed with the carrier.

Wettable powders are made up in the same manner as the dustconcentrates, excepting that about 1% to 5% by weight of a surfactantand about 1% to 5% by weight of a dispersant are added to theformulation. 1n practice, the wettable powders are generally dispersedin water or other suitable liquid and applied to the soil or foliage asa dilute spray.

Surfactants which may be used in preparation of the wettable powders arenaphthalene sulfonic acid condensate, polyoxyethylate vegetable oil,Sorbitan monooleate, monoand diglycerides of fatty acids, alkyl phenoxypolyoxyethylene ethanol and sodium alkyl naphthalene sulfonate. Themonocalcium salt of a polymerized alkyl aryl sulfonic acid and sodiumlignin sulfonate are representative of dispersants which can be used inthe wettable powder formulations.

Granular formulations can be prepared by applying an alcoholic orketonic solution of theactive material to a granular sorptive carrier,such as attapulgite, kaolin, activated carbon or corn cob grits.Non-sorptive carriers, such as granular limestone, walnut shell, coco- Inut shell or sand may be used in the preparation of granularformulations by (l)wetting the granules with a binder solution (e.g.,sodium lignosulfonate) or an alcoholic or ketonic solution of the activeingredient, and (2) coating the wetted particles with a dust or dustconcentrate containing the active compound or with an inert dustingagent, such as talc or clay.

Emulsifiable concentrates can be prepared by dissolving about 25% to 75%by weight of the active compound in a lower alcohol or ketone, asmentioned above, and admixing therewith from about 1% to by weight of anemulsifier. For use in the field, the concentrate is usually dispersedin water or other suitable diluent and applied as a liquid spray.

Effective control ofa wide variety of broadleaf weeds and grasses isusually obtained by application of a sufficient amount of the formulatedcomposition to provide about 0.06 pound per acre to 8 pounds per acre ofactive compound. Selective control of said weeds and grasses, on theother hand, generally requires only about 0.06 pound per acre to about 2pounds per acre of the active compound.

This invention is further illustrated by the following examples whichare not to be construed as limitative.

EXAMPLE 1 Preparation of Chloromethyl 1,1-dimethyl-2-propynyl etherCELCl; acm-c'z-on CI'LO 1101 9 HC CC-O-CH Ql Hydrogen chloride gas (80grams, 2.2 moles) is bubbled into a mixture of paraformaldehyde (60.2grams, 2.0 moles), and 2-methyl-3-butyne-2-ol (168.2 grams, 2.0 moles)in methylene chloride (500 ml.) over a 25 minute period, with constantstirring while the temperature is maintained between 2C. to 8C. Uponcompletion of the addition, the reaction temperature is allowed to riseto 10C.; then the lower organic phase is separated, washed with icewater, separated, and dried over anhydrous calcium chloride for 18hours. The methylene chlorde is removed by evaporation, and theresulting liquid distilled at reduced pressure to give a forerun of 10grams, boiling point 55C. to 57C./54 mm. and the major fraction as thechloromethyl ether. chloromethyl 1.1dimethyl-Z-propynyl ether. grams,53% boiling point 54C. to 58C./37 mm. to 40 The same chloromethyl etherwas also prepared in the absence of an added solvent in 32% yield.boiling point 39.5C. to 41.5C./l6 mm. to 17 mm.

EXAMPLE 2 Preparation of Chloromethyl l-methyl-2-propynyl ether l acc-ca-oa ciao Hc1-- Hydrogen chloride gas is bubbled into a suspensionofparaformaldehyde (30.1 grams, 1 mole) in 3-butyne- 2-o1 (70.1 grams, lmole), with constant stirring, at 30C. The exotherm is controlledbetween -l5C. and 5C., and the hydrogen chloride addition continueduntil the solid dissolves. Upon completion of the addition, the reactionis allowed to attain 15C. and sodium chloride added to aid theseparation of the organic layer. The upper organic layer is separatedand dried over anhydrous calcium chloride for 3 hours and distilledunder reduced pressure to give a forerun of 3 ml., boiling point 22C. to36C./35 mm. to 32 mm. and a major fraction 83 grams, 70%, boiling point36C. to 3'9C./32 mm. as the product chloromethyl l-methyl-Z- propynylether.

Hydrogen chloride gas (50 grams) is bubbled into a cooled, well-stirredsolution at 25C to 15C. of 2-methyl-3-butyne-2-o1 (84.1 grams, 1 mole)and acetaldehyde (44.05 grams, 1 mole) in dry methylene chloride (500ml.) containing a suspension of anhydrous calcium chloride (222 grams, 2moles). After the addition is complete, the reaction mixture temperatureis allowed to attain 5C. to 10C. for 30 minutes..and then is filteredand the filtrate concentrated to a volume of 240 m1. A ml. portion isdistilled under reduced pressure through a short column to give aforefun followed by the product l-chloroethyl 1,1-dimethyl-2- propynylether as a colorless liquid, 44.6 grams, 46%, boiling point 88C. to92C./55 mm. This product is extremely sensitive to air or moisture,fuming instantly.

EXAMPLE 4 Preparation of l-Chloroethyl 1-methy1-2-propynyl ether Iaczc-ca-oa 931, CHO HC1+ each Hydrogen chloride gas (25 grams) isbubbled for V2 hour into a cooled, well stirred solution at -25C. to-10C. of 3-butyne-2-ol (33.2 grams, 0.473 mole) and acetaldehyde (20.8grams, 0.473 mole) in dry methylene chloride (200 ml.) containing asuspension of calcium chloride (1 11 grams, 1 mole). After the additionis complete, the reaction mixture is allowed to attain 5C. to C. over a1 hour period; then the mixture is filtered, redried over anhydrouscalcium chloride (50 grams), and set aside overnight. After filtration,the filtrate is concentrated on a rotary evaporator, and the residualliquid distilled under reduced pressure through a short column to give a5 ml. forerun, followed by the product l-chloroethyl l-methyl-Z-propynylether, boiling point 68C. to 70C./111 mm. to 115 mm., 35 grams (56.3%).This product is extremely sensitive to moisture, fuming instantly.

EXAMPLE 5 Preparation of l-Chloroethyl 2-propynyl ether l-Chloroethyl2-propynyl ether boiling point 57C. to 63C./57 mm. to 60 mm. wasprepared in 47% yield by a procedure similar to Example 4. Similarly,the alkenyl ethers corresponding to the compounds of Examples 1 through5 can be prepared by substituting the appropriate alkenyl alcohol forthe alkynyl alcohol referred to in the Examples 1 through 5.

EXAMPLE 6 Preparation of m-( 3-Methoxy-3-methylureido)phenyl 1 ,1-dimethy1 2-propynyloxy)methyl]carbamate OCH, NH-CO-N\ tetrahzdrofuran Base6.1

OCH; NH-CO-N 9 2 HC' C-( 7-OCH NH-CO 1,1-Dimethyl-2-propynylchloromethyl ether (4 grams, 0.03 mole) is added dropwise with stirringat 0C. to 5C. to a dry ether (75 ml.) suspension of silver cyanate (4.5grams, 0.03 mole). After stirring for 1 hour at 0C. to 10C., then afurther hour at 23C., the mixture is filtered to give a solutioncontaining the generated isocyanate. (Infrared spectrum of the solutionshowed intense absorption at 'y224O cmf, i.e., N=C=O).

The ethereal isocyanate solution is added dropwise to a drytetrahydrofuran (20 ml.) solution ofl-(mhydroxyphenyl)-3-methoxy-3-methylurea (5.88 grams, 0.03 mole)containing triethylamine (3.34 grams, 0.031 mole) at 23C. The additionis slightly exothermic, and the temperature rises to 27C. After stirringfor 45 minutes, a solid separates and the mixture is filtered, and thefiltrate evaporated to an oil which is dissolved in chloroform.Extraction of this layer with aqueous sodium hydroxide 1%, andacidification of this layer, gives recovered ureidophenol, 1.5 grams.The solid, filtered from the reaction, is water washed and dried to give4.34 grams, 58%, melting point 121C. to 122C.

An analytical sample has melting point 121C. to 122C. prepared bycrystallization from benzene-nhexane.

9H3. Analysis Calcd. for C H ,N O C, 57.30; H, 6.31; N. HC;Q C O CH 1 Hether 12.53. Found: C, 57.45; H, 6.44; N, 12.59.

a Following the above procedure yields the compounds H3 set forth inTables Ill and 1V below.

(Alkynyloxy)alky1 and (Alkeny1oxy)a1ky1 Carbamates 2 NH-CO-N 3O-lTIO-NllR Melting R R R Point 1 Yield Solvent of Analy e5 2 3 1 C.(Crystallized) Crystallization Calculated Found -CH3 Cl'i-CH2-O-CH2-CH=CH2 133-13 1 12. 3 Benzene V C 57. 32 57 .06 H 6 53 6 17N, 14.35 1 1.16

16 CHzCl-g. The methylene chloride layer is then washed with water (100ml.), washed with a NaOH solution (1% w/v, 100 ml.), water washed,separated, dried over anhydrous CaCl filtered, and evaporated to a solid5 which is crystallized from benzene-hexane to give 0.37

grams of product with a melting point identical to material preparedusing triethylamine as base.

g OCH; N EXAMPLE 9 The postemergence herbicidal activity of thecompounds of the invention is demonstrated by the following tests,whereina variety of monocotyledonous and dicotyledonous plants aretreated with test compounds 9 5 dispersed in aqueous acetone mixtures.1n the tests. ECH seedling plants are grown in 2-inch squareplastic pots6 for about two weeks. The test compounds are dispersed in 50/50acetone/water mixtures containing 0.5% v/v surfactant in sufficientquantity to provide the equivalent of about 0.06 pound to 4 pounds peracre of active compound when applied to the plants through a spraynozzle operating at psi. for a predetermined time. After spraying, theplants are placed on greenhouse benches and are cared for in the usualmanner, commensurate with conventional greenhouse practices. Two weeksafter treatment, the seedling plants are examined and rated according tothe rating system provided below. The, data obtained are reported inTable V below where it can be seen that the preferred comable broadleafweeds and grasses.

Table V Postemcrgence Herhicidal Activity Annual Weeds Crops LA MU PlRAG MG BA CR GRF WO VE COR COT SOY 15 EXAMPLE 8 Preparation ofm-(3-Methoxy-3-methylureido)phenyl eated with 20% HCl-(v/v) 30 poundsare highly effective for the control of undesir- Treatment 1b./Acre l,1-dirnethyl-2-propynyloxy)methylJearbamate I H; O-C-C dryt'etrahvdrofura quinoline ll N-C-NH (Hi 0 The isocyanate ether solutionabove (38 ml., 0.015 mole) is added with constant stirring at roomtempera- 1-(m-hydroxyphenyl)-3-methoxy-3-methylurea 5 Compound OCN-Cture (23C.) to a dry tetrahydrofuran solution (20 ml.) of

(2.94 grams, 0.015 mole) containing quinoline (15 ml.), and the reactionstirred overnight at room temperature. A tar separates. The reactionmixture is decanted away from the tar and evaporated to an oil in acrystallizing dish. This oil is tr until the solution is acidic, andthen extracted with m-(3-methoxy-3- methylureido)pheny1[(1.1-

dimethyl-Z-propynyloxy)methyl]carbamate m-( 3.3-dimethylureido)phenyl[(allyloxy )methyl lcarbamate m-( 3-methoxy-3- methylureido)phenyl1(allyl0xy )methyl lcarbamate m-( 3,3-dimethy1ureido)phenyl[(2-propynyloxy )methyl lcarbamate m-( 3,3-dimethylureido )phenyll-methyLZ-propynyloxy)methyl lcarbamate m-( 3,3-dimethylureido)phenyl[(1,1-dimethyl-2- propynyloxy)methy1lcarbamate m-( 3-methoxy-3-methylureido)pheny1 [(2-propyny1oxy )methyllcarbamate TABLE V CntinuedPostemcrgence Herbieidal Activity Treatment Annual Weeds Crops Compoundlb./Acre LA MU Pl RAG MG BA CR GRF WO VE COR COT SOY R m-(3-methoxy-31.00 9 9 9 9 9 9 9 9 9 9 9 9 9 9 methylurcido)phenyll-methyl-2-propynyloxy)methyllcarbamate 2-chl0ro-4-(3,3- 4.00 9 9 9 9 99 9 9 8 9 9 9 9 8 dimethylureido)phenyl l.l-dimethyl-2- propynyloxy)methyl lcarbamate m-(B-methoxyd- 4.00 9 9 9 9 9 7 7 9 9 9 7 9 9 smethylureido)phenyl l(2-propynyloxy)ethyllcarbamate 1.00 9 9 9 9 9 2 i 87 9 l 7 9 2 0.25 9 9 9 7 7 0 0 1 0 9 0 2 9 0 0.13 8 9 9 l 3 O 0 0 0 3 O2 2 0 2chioro-4-( 3-methoxy-3- 4.00 9 9 9 9 9 3 6 8 9 9 5 9 9 8methylureido phenyl [t l.l-dimethyl-2- propynyloxy)methyllcarbamate 1.009 9 9 7 5 0 2 2 2 8 l 7 5 l 0.50 8 9 8 1 5 0 0 1 0 1 1 t 3 0 0.25 2 9 s0 0 0 0 0 0 0 3 3 0 m-( 3-methoxy-3- 1.00 9 9 9 9 9 2 2 9 8 9 6 9 9 7me1hylureido)phenyl [l( l-methyl-2-propynyloxy)ethyllcarbamate m-(3-meth0xy-3- 4.00 9 9 9 9 3 7 8 7 9 7 9 9 3 methylureidolphenyl[l-(1.l-dimethyl-2- propynyloxy)ethyllcarbamate 1.00 9 9 9 9 7 1 1 2 9 59 1 0.25 9 9 9 l 5 0 0 l 1 9 0 5 8 0 0.13 9 5 8 l l 0 0 0 0 7 0 3 7 0EXAMPLE Plant Abbreviations LA Lambsquarters MU Mustard PI Pigweed BABarnyard grass CR Crab grass GRF Green foxtail W0 Wild oats COR c Thepreemergence herbicidal actlvity of the comggl pounds of the inventionis exemplified by the following O 11 RAG f s tests 1n which the seeds ofa variety of monocotyle- MG Morning-glory donous and dicotyledonousplants are separately mixed I 5/55 leaf with potting soil and planted ontop of approximately /1 Reduction in Growth one inch of SQli in separatetwo-inch square plastic Ramg System; Compared Check! pots. Afterplanting, the pots are sprayed with the se- 0 no ff 0 lected aqueousacetone solution containing test com- 1 ploslsqibli feffect 11-12 poundin sufficient quantity to provide the equivalent 51g te ect 3 modemeeffect 2640 ,0 of about 0. l 3 pound to 4 pounds per acre oftest com 5definite injury 41-60 pound per pot. The treated pots are then placed on6 herbicidal effect 61-75 7 good herbicidal 6mm 7&9) greenhouse benchesand cared for in accordance with 8 approaching complete x111 9greenhouse procedures. Three weeks after treatment, 3 g p h d r h l l gthe tests are terminated and each pot is examined and T a 6 p yslo oglcama rated according to the rating system set forth in the preformationbut with an over-all effect less than a 5 0n the rating scale.

"Based on visual determination of stand. silo. vigor. chlurosis. growthmalformation and over-all plant appearance.

ceding example. The results of these tests establish the herbicidalproficiency of the test compounds for controlling a variety ofundesirable plant species.

21 v 22 We claim; 3. A compound according to claim 1, m-(3 -methoxyl. Acompound having the formula: 3'methylureidmphenyl Ypropynyloxy)methyl]-carbamate. O 4. A compound according to claim 1,m-(3,3- R dimethylureido)phenyl [(1,1-dimethyl-2- 1i, -HN-CO Rpropynyloxy)methyl]-carbamate.

N-CO-N 5. A compound according to claim 1, m-(3.3- dimethylureidolphenyl[(allyloxy)methyl]carbamate. A B5 6. A compound according to claim 1,m-(3.3- dimethylureido)phenyl [(2-propynyloxy)methyl]carbamate. whereinR is hydrogen, hydroxyl or alkyl C -C R is 7. A compound according toclaim 1, m-(3,3- hydrogen, alkyl C -C or alkoxy C -C R is hydrogen,dimethylureido)phenyl l-methyl-2-propynyloxy)mealkyl C -C alkoxy C -Cthyl]carbamate.

3 3 R -czc-c-o-cH or R CH=C C-OCH-; Rt, is

l I R R R 3 r R -C C-C-OCH- Or R -CH=C COCH-;

8 9 i II2 R is hydrogen or n-alkyl C -C R and R are hydrogen 8. Acompound according to claim 2 wherein R is or alkyl or alkyl C -C R andR are hydrogen, alkyl C -C or halogen; and A is hydrogen, halogen oralkyl C -C4; provided that A and -O -CONHR are metaand 1 R R5 para-,respectively, or paraor meta-, respectively; and provided that R; ishydrogen when R is either R C- -CCO-CH R 3 e a 7 8 or 9 9 9. A compoundaccording to claim 2 wherein R is R R R 2. A compound according to claim1, wherein R is R CH=C C-O-CH- hydrogen; R is methyl or methoxy; R ismethyl; A is hydrogen; R NHCO-O- is metato the ureido group; 40 R R.

R R R R and R are as described in claim 1, and R is hydrogen.

1. A COMPOUND HAVING THE FORMULA:
 2. A compound according to claim 1,wherein R1 is hydrogen; R2 is methyl or methoxy; R3 is methyl; A ishydrogen; R4NHCO-O- is meta- to the ureido group; R4, R6, R7, R8 and R9are as described in claim 1, and R5 is hydrogen.
 3. A compound accordingto claim 1, m-(3-methoxy-3-methylureido)phenyl((1,1-dimethyl-2-propynyloxy)methyl)-carbamate.
 4. A compound accordingto claim 1, m-(3,3-dimethylureido)phenyl((1,1-dimethyl-2-propynyloxy)methyl)-carbamate.
 5. A compound accordingto claim 1, m-(3,3-dimethylureido)phenyl ((allyloxy)methyl)carbamate. 6.A compound according to claim 1, m-(3,3-dimethylureido)phenyl((2-propynyloxy)methyl)carbamate.
 7. A compound according to claim 1,m-(3,3-dimethylureido)phenyl ((1-methyl-2-propynyloxy)methyl)carbamate.8. A compound according to claim 2 wherein R4 is
 9. A compound accordingto claim 2 wherein R4 is